Speakerphone and Audio

The Nexus 4 has a small vertical notch cut out of the back glass for its speakerphone port. The unfortunate part is that when the Nexus 4 is laid display-up like I always place phones for testing under our digital sound level datalogger, it is quite muted since there is no gap in the cavity for sound to escape through.

With the phone raised, however, the Nexus 4 turns out to be decently loud, which matches my subjective impressions using the device for Google Navigation over the past few days.

Noise Suppression

The Nexus 4 has a pair of microphones for noise suppression both when on calls, and also for the increasingly important task of reducing noise on ASR (Automatic Speech Recognition) workloads like Google Now. I believe the Nexus 4 is using Qualcomm’s Fluence for this task, which is an adaptive beamformer system.

To test its efficacy, I turned to the industry standard babble track and ramped volume in front of a pair of speakers to 94 dBA (very loud) and then back down while recording the mobile-terminated end of the call on my PC. I should note that when I run these tests I always originate and terminate the call on the same mobile operator (in this case T-Mobile) if possible.

The Nexus 4 does a pretty decent job at canceling noise on my test call. The Galaxy Nexus noise rejection performance quite honestly never was that spectacular, and getting better noise filtering is going to be an increasingly important part of the speech recognition battle on these platforms.

Audio

Inside the Nexus 4 is a Qualcomm WCD9310 audio codec, which we’ve seen in other devices like the MSM8960-based Galaxy S 3s and a few other phones. Measuring sound quality is probably the number one requested addition to our reviews, and still is a rather nebulous thing to measure at times. For this I worked together with the ever-awesome François Simond (@supercurio) to measure sound quality on the Nexus 4 using RMAA on my desktop equipped with an ASUS Xonar Xense sound card.

Subjectively the Nexus 4 doesn't sound terrible to my ears on a pair of SE535s and listening to music at half volume or less. Objectively however the results are less than awesome thanks to a combination of things. First, audioflinger is set to 48 kHz which results in software resampling causing artifacts for 41.1 kHz source material. Second, there appears to be different modes that the Nexus 4 switches into depending on your volume level, and the frequency response plots show these different plots at the number of different volume levels we tested. We're going to update with some thoughts from Francois about the Nexus 4 soon, for now I think the Nexus 4 sounds ok at least when it comes to the most glaring of things — I couldn't detect any background hiss or whine as the SoC changes states, which is a huge percentage of what I normally wind up hearing on smartphones.

Post Your Comment

189 Comments

I'm glad you confirmed the thermal throttling hypothesis, but it's a shame that it's happening at all. While no Google or LG exec is going to come out and tell everyone to use their phone in the cold, I see this turning into the Android version of the "your holding it wrong" meme. Perhaps Google should ship some capacitative gloves so Canadians and Scandinavians can enjoy their phones under ideal conditions ;P?

Also, battery performance. It's half the iPhone 5's. Half.

Given the price and the nexus pedigree, I'm still going to buy this phone, warts and all. But the performance of the device in browsing and battery life is terribly disappointing.Reply

That suggests that the tests are not very useful.Frankly, I really like the idea of Vellamo. Testing interface performance is really useful.The web browsing test might also be useful if it is well done (not sure if enough time is provided between page loads to actually read the page).Perhaps use of a framework that takea actual apps and feeds them dummy data to simulate usage.Testing is hard... Reply

The one time they could have gone with a slighly out of date SoC (the MSM8960 with its more efficient integrated baseband, or possibly the PRO) they didn't... ending up with a very power hungry platform that throttles and barely has enough battery life. Personally, I think I will disable two of the cores, but it's very appreciable that they're moving faster than before. I was really hoping for an OMAP5 (the first BIG.little A15 implementation) in the next nexus phone, obviously a few months from now, but I'll make do with the S4.

It is, as usual, great how google keeps an eye on NAND performance, it really is a bottleneck in modern smartphones. Hopefully something better than 0.8MB/s random writes will be available in the near future... yes, it's 3 times faster than the competition, but still too low. We need 4/5.

I'm quite a bit against all this "high build quality" (which is apparently all about non-plastic materials) trend: not that I don't like better built phones, but plastic is FINE. It just has to be properly used, avoiding tacky chrome and glossy parts: the upside of having a lighter chassis with a removable door, and thus a repleaceble battery (which can probably be larger thanks to the spared weight) largely overcomes the improved aesthetics. Not to mention it's much less prone to serious damage as it manages to absorbs impacts well.A glass back might be cool, but I won't notice it anymore after a week... until it breaks.The real problems are Korean designers, not plastic materials.

In the end, higher battery life and storage space would have been much better, but at this price I won't complain, there's nothing even nearly as good. Heck, even $200 more would have been fair - and still cheaper than the competition.

Still, such a non-replaceable low lasting battery can and will be a dealbreaker to many just as much as the lack of storage. But the price is good enough to make me come to a compromise, disable 2 cores in the kernel and start carrying around a portable charger and OTG cable.I wonder if anyone will make a nice battery cover with integrated storage :)Reply

I think you seriously underestimate how long most PhD theses are. This could probably easily double as an engineering undergrad senior/final project though, as could many of our more in-depth reviews.Reply